For factory loads I like a corelokt cartridge. However, I hand load all of my ammunition now and have become addicted to the nosler accubond. They are a bullet with controlled expansion so they retain almost of their mass on impact. I have personally removed .308 200gr Accubond bullets from a clay bank that are about the diameter of a dime and have retained almost 98% of their original mass. They are an impressive bullet.

Keep in mind that each gun shoots bullets differently. For instance, my .270 loves a 140gr accubond, 1/2 inch group at 100yds. My 30-06 hates the accubond and the sierra game king, but loves the hornady interbond bullet in 165gr. If you reload, buy different bullets and powder and experiment with different loads. If you don't reload, just buy different brands of factory loads at different grains and see how they group. For the 30-06 I like a 150 or 165 gr bullet. I reloaded the 200gr bullets just to see how they would pattern.